c# - 从组合框 C# 表单发送文本作为 SQL 过程的输入

Question

我的代码遇到了问题。我有一个 SQL 数据库和两个名为:类别和产品的表。我已经创建了一个名为:viewByCat 的程序，当我选择要在组合框中显示哪种类别时，此程序将为我显示一个类别的所有产品。例如:我在组合框中有衣服、鞋子、猫，当我选择“衣服”=>时，它会向我显示所有存储在产品中的衣服。我如何传递组合框的文本作为程序的输入，看看我的代码:

SQL

create proc viewByCat 
@keywords nvarchar(30)
as
select PD.ProID , PD.ProName , PD.TinyDes ,PD.FullDes ,PD.Price ,PD.CatID ,PD.Quantity 
from Categories CT join Products PD on CT.CatID = PD.CatID 
where CT.CatName = @keywords
go

升 C 音

  private void btn_viewByCategories_Click(object sender, EventArgs e)
    {
        //initialize source will be displayed on dgv
        List<Produce> src_produces = new List<Produce>();
        //create SqlConnection
        //create connection
        string connectionstring = @"server=.\SQLEXPRESS;database=sellingManager;integrated security=true";
        //create SqlConnection with above string
        using (SqlConnection cnn = new SqlConnection(connectionstring))
        {
            //create SqlCommand
            SqlCommand cmd = cnn.CreateCommand();
            //use SqlCommand to present for procedure
            cmd.CommandType = CommandType.StoredProcedure;
            //invoke procedure will be used
            cmd.CommandText = "viewByCat";
            //open connection
            cnn.Open();
            //
            using (IDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
            {
             //something...
            }

Answer 1

您需要更新您的 C# 代码。请引用以下代码:

        SqlCommand cmd = new SqlCommand("viewByCat]", connectionstring);
        cmd.CommandType = CommandType.StoredProcedure;

        cmd.Parameters.Add("@keywords", SqlDbType.NVarChar).Value ="Your Selected value from combo box";


        cnn.Open();
        DataTable dt = new DataTable();
        using (SqlDataAdapter sdadptr = new SqlDataAdapter(cmd))
        {
            sdadptr.Fill(dt);
        }
        cnn.Close();
        return dt;